As mentioned in the overview, the event handling function receives an event object, which contains many properties and methods. The event object is most commonly used to prevent the default action of the event via the preventDefault method. However, the event object contains a number of other useful properties and methods, including:
The mouse position at the time the event occurred, relative to the top left of the page.
The type of the event (e.g. "click").
The button or key that was pressed.
Any data that was passed in when the event was bound.
The DOM element that initiated the event.
Prevent the default action of the event (e.g. following a link).
Stop the event from bubbling up to other elements.
In addition to the event object, the event handling function also
has access to the DOM element that the handler was bound to via the
keyword this. To turn the DOM element into a jQuery object
that we can use jQuery methods on, we simply do $(this),
often following this idiom:
var $this = $(this);
Example 5.8. Preventing a link from being followed
$('a').click(function(e) {
var $this = $(this);
if ($this.attr('href').match('evil')) {
e.preventDefault();
$this.addClass('evil');
}
});
Copyright Rebecca Murphey, released under the Creative Commons Attribution-Share Alike 3.0 United States license.